Ziomall, it sounds to me like you want to edit a table and save it with the changes so that they are available every time you use it.
If that is the case, insert the table into a drawing ('Table>Insert>From file'). Highlight the cell with the text you want to add/change, RMB the menu and select 'Properties'. In the Note Properties interface, it gives you a large area to enter or edit text. If there is text in the cell already, it will show in the text area. Type the letter 'a' in the box. Click the 'Text Style' tab at the top, locate the Character section and the Font window. Open this to get a list of the available fonts. You should find CAL_GREK. Select it and you should get the Greek equivalent of our letter 'a', in other words, alpha. You have all the other properties available to chage on this Style page, as well. Finish editing, go back to 'Table' and find 'Save table>As table file'. When the file dialogue opens, find the 'Look in' box, open it to get the list storage places. You should see one that says 'System Formats'. Select this and you should see the table you just edited. Pick one, if you wish to overwrite an existing table or give it a different name.
You can also do this if you have a table saved in a format. Slightly different procedure.
David Janes